The OnClientTextChange client-side event occurs when the user enters custom text in the input field of RadComboBox (if AllowCustomText property is True). OnClientTextChange doesn't fire until the user hits Enter or clicks outside the combobox.

The event handler receives two parameters:

The instance of the combobox firing the event.

An eventArgs parameter containing the following methods:

get_domEvent() returns the DOM event object.

set_cancel lets you prevent the combobox from doing a postback (if AutoPostBack property is True), but doesn't let you prevent the text from changing.

You can use this event to perform any client-side actions with the entered text: